Japan on Saturday began its first military expansion at the western end of its island chain in more than 40 years, breaking ground on a radar station on a tropical island off Taiwan.
The move risks angering China, locked in a dispute with Japan over the nearby Senkaku Islands that both countries and Taiwan claim.
Defense Minister Itsunori Onodera, who attended a ceremony on Yonaguni Island to mark the start of construction, suggested the military presence could be enlarged to other islands in the seas southwest of Japan's main islands.